ARM: dma-mapping: add support for dma_get_sgtable()
This patch adds support for dma_get_sgtable() function which is required
to let drivers to share the buffers allocated by DMA-mapping subsystem.
Generic implementation based on virt_to_page() is not suitable for ARM
dma-mapping subsystem.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8e505b9..51278ed 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -125,6 +125,7 @@
.alloc = arm_dma_alloc,
.free = arm_dma_free,
.mmap = arm_dma_mmap,
+ .get_sgtable = arm_dma_get_sgtable,
.map_page = arm_dma_map_page,
.unmap_page = arm_dma_unmap_page,
.map_sg = arm_dma_map_sg,
@@ -661,6 +662,21 @@
}
}
+int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
+ void *cpu_addr, dma_addr_t handle, size_t size,
+ struct dma_attrs *attrs)
+{
+ struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
+ int ret;
+
+ ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+ if (unlikely(ret))
+ return ret;
+
+ sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+ return 0;
+}
+
static void dma_cache_maint_page(struct page *page, unsigned long offset,
size_t size, enum dma_data_direction dir,
void (*op)(const void *, size_t, int))
@@ -1172,6 +1188,20 @@
__iommu_free_buffer(dev, pages, size);
}
+static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
+ void *cpu_addr, dma_addr_t dma_addr,
+ size_t size, struct dma_attrs *attrs)
+{
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+
+ if (!pages)
+ return -ENXIO;
+
+ return sg_alloc_table_from_pages(sgt, pages, count, 0, size,
+ GFP_KERNEL);
+}
+
/*
* Map a part of the scatter-gather list into contiguous io address space
*/
@@ -1431,6 +1461,7 @@
.alloc = arm_iommu_alloc_attrs,
.free = arm_iommu_free_attrs,
.mmap = arm_iommu_mmap_attrs,
+ .get_sgtable = arm_iommu_get_sgtable,
.map_page = arm_iommu_map_page,
.unmap_page = arm_iommu_unmap_page,